product download rules

these are the current product download rules:

          /*
            Changes to the search keys rebuild routines for V3.4.0
            Host side:
            1. When exporting product changes, set PRODSORT = -1 in changed product download records.
               When doing a full product export, set PRODSORT = 0
            Client side:
            1. during a download session, keep track of what is downloaded:
               (a) a full product file (e.g. "product.sql")
               (b) one or more product change files (e.g. "product_chgs_20091209081420.sql")
            2. If (a), or (a) and (b), check a new ini param "RebuildSearchKeys", with possible values:
               "YES": always do a full search key rebuild when a full product file is downloaded
               "ASK": ask the user whether to do a full search key rebuild.
               "NO": never do a full search key rebuild.
            3. If (b) only, then do an incremental rebuild of TEXTKEYS, and do not rebuild SEARCHVALS at all.
               For each product with a PRODSORT of -1, delete existing TEXTKEYS records, and then do a rebuild
               of the keys for that product.
            4. Always as a last step, renumber the PRODSORT value in PRODUCTS (for next/prev logic).
          */